Augmented seventh chord

The augmented seventh chord , or seventh augmented fifth chord,^[1] or seventh sharp five chord is a dominant seventh chord consisting of an augmented triad with a minor seventh. ^[2] Thus, it consists of a root, major third, augmented fifth, and the minor seventh.^[3] Thus in the key of C major it would be C, E, G-sharp, and B-flat as in the figure. It may be notated with the chord symbols C+7, Caug7,^[3] or C^7♯5, and can be represented by the integer notation {0, 4, 8, 10}.

The root is the only optional note in an augmented seventh chord, the fifth being required because it is raised^[4]. This alteration is useful in the major mode because the raised 5th creates a leading tone to the 3rd of the tonic triad.^[2] See also dominant.

In rock parlance, the term Augmented seventh chord is sometimes confusingly and erroneously used to refer to the so-called "Hendrix chord", a 7♯9 chord which contains the interval of an augmented ninth but not an augmented fifth.^[5]

The augmented minor seventh chord may be considered an altered dominant seventh and may use the whole-tone scale, as may the dominant seventh flat five chord^[7]. See chord scale system.

Augmented seventh chord table

See also

• Augmentation (music)

Sources